ASNSW Book Reviews

“A TRAVELLER’S GUIDE TO MARS: THE MYSTERIOUS LANDSCAPES OF THE RED PLANET”

This is a great little book, now available from good bookshops for only $45.

For years and years there have been numerous articles in popular magazines - like Sky and Telescope - on Martian landscapes. Even to Earth Scientists like myself however, it is difficult to build up a clear planetwide picture of what is going on.

This book fixes that. It is divided into 7 parts covering (1) History and Mystery, (2) Noachian Mars - The Oldest Provinces, (3) The Mars Landings, (4) Hesperian Mars - A Time of Transition, (5) Martian Meteorites, (6) Amazonian Mars - The Red Planet Today, and, (7) Where do we come from, where are we going?

Subsections have engaging titles like The Mystery of the Martian Soil, Craters and the Depth to Ice, The Secret of an Ancient Ocean, Hematite Deposit No 1, Land of Dust Devils, Largest Volcano in the Solar System, etc.

In précis, the main geological eras on Mars are:

• Noachian Era - 4500-3500 MY ago. An era of active erosion and intense volcanic activity, with initial intense impact cratering declining quickly. The atmosphere was denser, at least in the early part, and water flowed and pooled in places - possibly forming saline lakes or oceans.
• Hesperian Era - 3500-2500/2000 MY ago. An era of transition to drier/dustier conditions. River-forming activity declined and underground ice growth increased. Local melting caused catastrophic floods and ground collapses forming chaotic terrain.
• Amazonian Era - 2500-2000 MY ago until today. An era moving to a dry, dusty Mars with declining rates of volcanic, erosional and impact activity. Water was/is still occasionally released to surface-due to (?) axial tilting/solar melting.

Every type of volcanic, impact, erosional, depositional and tectonic feature is illustrated in the book, and explained at various scales in great clarity, often reverting to terrestrial analogues. Subjects covered include:

• Rampart craters in frozen ground
• High latitude glacial flow (rock/ice) features
• Crater exhumation of ancient sediment layers
• Multigenerational (fossil) dunes
• Dust devil trails
• Water-formed crater-flank valley networks
• Catastrophic floods, teardrop islands, and source “chaotic” terrain
• Hillside gully water outbursts and arctic analogs
• Landing sites - boulder fields, frost cracking, “rust” and duricrusts
• Evidence for recent (20 MY old) lava flows
• CO² and H²O polar caps, strange “sublimation” features
• Possible micro-fossils in a Martian meteorite
• Dark features relating to unweathered basalts and olivine crystals
• Canals of Xanthe - Lowell at least got them right
• Bi-polar magnetic (plate tectonic) stripes pre 3900 MY ago

And much, much more, including two handy fold-out maps at the front of the book.

A good read - I hope people like it as much as I did. If members want to share information and ideas on this or related topics, I am contactable c/- The ASNSW